Amnesia is scary and I'm stuck at the cistern/controlroom

[Hunter of Shadows]

So.. I have been into the torture rooms, gotten every piece of orb, and 2 in the Choir.
I guess I have to find one more (looks like 1 more is missing)
Where could I find it? Have found one in the "cow room" and one somewhere I don't remember

Have been looking all over the place, but couldn't find any other..

Also, before you go to the torture rooms, there's a well or something, but there's no bucket, just a rope.
Anything I have to do there? It sounds like there's some scary creature down there whenever I throw rocks in :<

follow the pipes on the ceiling, they lead to the different torture chambers